While tensions flared this week as Iran briefly held 10 U.S. sailors who mistakenly trespassed into its waters, a Marin County man continued his relentless crusade to remind the world of someone Iran has held for so much longer — his brother, Washington Post journalist Jason Rezaian.

But even after traveling to Washington, D.C., many times on this mission in the past 18 months, Ali Rezaian, 45, found himself someplace new and unexpected on this visit: in the House of Representatives, watching President Obama’s State of the Union address.

Obama made only brief reference Tuesday to the nuclear arms deal his administration and five other nations made with Iran last year, and none to the plight of the Bay Area family that has found itself in the middle of an international crisis.

After their father, a rug merchant with stores in Mill Valley and Petaluma who emigrated to America from Iran in 1959, died in 2011, their American-born mother, a family and marriage therapist well-known in Marin County, moved to Turkey. But now she has taken an apartment in Tehran, so she can visit her younger son in jail whenever authorities allow it.

And Ali Rezaian, a biotech consultant, has clocked many hours and traveled many miles to visit with lawmakers, diplomats and advocacy groups from Washington, D.C, to the United Nations in New York to the U.N. Human Rights Commission in Geneva, Switzerland. On Tuesday, he was Rep. Jared Huffman’s guest at the president’s annual address to Congress — though he’d much rather be sitting beside his brother at an Oakland A’s game, or at home in Mill Valley watching his son play with his beloved Uncle Jason.

“It’s absolutely unbelievable he’s been held this long, and we’re working any angle we can to get help,” Ali Rezaian said Wednesday in a telephone interview from Washington.

Jason Rezaian, 39, has been based in Iran as a journalist since 2008 and became the Post’s bureau chief in 2012. Iranian authorities arrested him and his wife, also a journalist, in July 2014; his wife was released that October but he remained jailed. He was charged with espionage in April 2015, tried in secret by Iran’s Islamic Revolutionary Court, and convicted later last year.

Huffman, D-San Rafael, said concerned constituents began calling him almost as soon as Jason Rezaian was first detained.

“I reached out to Ali and his mother because I wanted to make sure whatever I did was consistent with the advice and preferences they had,” Huffman said. In deference to their wishes, they initially kept a low profile in hope that the U.S. government and the Washington Post could “work this out quietly with Iran.”

Now, however, “we have to keep a very high profile on Jason’s innocence, on the imperative of getting him released,” he said. “His psychological and physical health are in jeopardy there and we want to maintain international pressure on Iran.”

Some critics say the deal that the Obama administration and five other nations struck with Iran last year to curtail its nuclear capabilities should have included Rezaian’s release. But Abbas Milani, director of Iranian Studies at Stanford University and co-director of the Iran Democracy Project at the Hoover Institution, is among experts who say so important and delicate an international agreement couldn’t have been allowed to balance on one man’s freedom.

Still, Milani said he wishes U.S. diplomats had made the case more visible at the nuclear talks. “Some mention of it without necessarily predicating the passage of the deal … would’ve gone a long way, both in improving the U.S. position and in encouraging human rights activists inside Iran and outside that the West is still interested in this,” he said.

While Iranian President Hassan Rouhani and Foreign Minister Javad Zarif have seemed willing to let Rezaian go, the Iranian judiciary and Islamic Revolutionary Guard Corps which are actually holding him don’t want the relatively moderate Rouhani to earn that political capital.

“Almost every week they try to do something that would muddy the water and make it more difficult … to return Iran to being a full law-abiding country, not a pariah but a player,” Milani said — meaning Iran’s fractious internal politics are as much a barrier to Rezaian’s freedom as rocky U.S.-Iran relations.

Huffman said discussions about Rezaian on the nuclear talks’ sidelines at least opened a channel, and have intensified since then. “We are continuing to have direct nation-to-nation dialogue with Iran on this issue,” he said — far preferable to communicating through Swiss diplomats as middle-men, since Iran and the U.S. still lack regular diplomatic relations.

If those talks and international pressure don’t win Rezaian’s freedom soon, “there may well be a need to create new hostage-related sanctions” against Iran, Huffman said, a bill he’d be happy to carry. “There would be no shortage of bipartisan support for that kind of thing,” he said.

Ali Rezaian said he met Wednesday with the Washington Post team that’s supporting efforts to free his brother, and he appreciates Huffman and his staff’s efforts to keep the situation front and center with key congressional committees.

But it all feels so distant from the brothers’ childhoods at Marin Country Day School and Marin Academy, from the family gatherings they’ve had over the years, and from the lives to which they both hope to return. Jason Rezaian now has been held by Iran longer than any nation has ever imprisoned a Western journalist.

“It’s baffling that this continues, it’s a tragedy,” his brother said. “They can make all the excuses they want, but those are the facts.”